Number System Practice Test 4

Question : 5 of 40

Marks: +1, -0

There are four numbers A, B, C and D. Average of the first three i.e., A, B and C is 15 and that of B, C and D is 16. If the last number, i.e., D is 19, then the first number is—

Validate

Solution:

{A+B+C}/3=15

⇒A+B+C=45

... (i)

{B+C+D}/3=16

⇒B+C+D=48

... (ii)
∴ B + C + 19 = 48 or, B + C = 48 – 19 = 29
But, A + B + C = 45
Putting the value of B + C = 29 in the above equation (i), we get
A + 29 = 45
∴ A = 45 – 29 = 16.

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